function FilterHtml::filterElementAttributes

Filters attributes on an element according to a list of allowed values.

Parameters

\DOMElement $element: The element to be processed.

array $allowed_attributes: The list of allowed attributes as an array of names and values.

File

core/modules/filter/src/Plugin/Filter/FilterHtml.php, line 159

Class

FilterHtml

Provides a filter to limit allowed HTML tags.

Namespace

Code

protected function filterElementAttributes(\DOMElement $element, array $allowed_attributes) {
    $modified_attributes = [];
    foreach ($element->attributes as $name => $attribute) {
        // Remove attributes not in the list of allowed attributes.
        $allowed_value = $this->findAllowedValue($allowed_attributes, $name);
        if (empty($allowed_value)) {
            $modified_attributes[$name] = FALSE;
        }
        elseif ($allowed_value !== TRUE) {
            // Check the list of allowed attribute values.
            $attribute_values = preg_split('/\\s+/', $attribute->value, -1, PREG_SPLIT_NO_EMPTY);
            $modified_attributes[$name] = [];
            foreach ($attribute_values as $value) {
                if ($this->findAllowedValue($allowed_value, $value)) {
                    $modified_attributes[$name][] = $value;
                }
            }
        }
    }
    // If the $allowed_value was TRUE for an attribute name, it does not
    // appear in this array so the value on the DOM element is left unchanged.
    foreach ($modified_attributes as $name => $values) {
        if ($values) {
            $element->setAttribute($name, implode(' ', $values));
        }
        else {
            $element->removeAttribute($name);
        }
    }
}